Project Diana pointed an SCR-271 bed-spring radar antenna at the rising moon #OTD in 1946 and broadcast a series of short signals.

Each signal echoed off the moon and returned about 2.5s later, proving that radio could penetrate the ionosphere.

This was an important result for the nascent field of satellite communications, but early news reports on the project ignored the contributions of a Black physicist.

Image: https://cybercoe.army.mil/SIGNALSCH/OCOS/HISTORY/history_project_diana.html